Recent findings from University of Alabama highlight research in cystic fibrosis.

"The ubiquitin-proteasome pathway and autophagy are the two major mechanisms responsible for the clearance of cellular proteins. We have used the yeast Saccharomyces cerevisiae as a model system and the cystic fibrosis transmembrane conductance regulator (CFTR) as a model substrate to study the interactive function of these two pathways in the degradation of misfolded proteins," scientists in the United States report (see also Neurodegenerative Disease).

"EGFP-tagged human CFTR was introduced into yeast and expressed under a copper-inducible promoter. The localization and degradation of EGFP-CFTR in live cells were monitored by time-lapse imaging following its de novo synthesis. EGFP-CFTR first appears within the perinuclear and sub-cortical ER. and is mobile within the plane of the membrane as assessed by fluorescence recovery after photobleaching (FRAP). This pool of EGFP-CFTR is subsequently degraded through a proteasome-dependent pathway that is inhibited in the prel-1 yeast strain defective in proteasomal degradation. Prolonged expression of EGFP-CFTR leads to the sequestration of EGFP-CFTR molecules into ER structures called ER-associated complexes (ERACs). The sequestration of EGFP-CFTR into ERACs appears to be driven by aggregation since EGFP-CFTR molecules present within ERACs are immobile as measured by FRAP. ...